Boundary conditions for the Néel order parameter in a chiral antiferromagnetic slab

Abstract

Understanding of the interaction of antiferromagnetic solitons including domain walls and skyrmions with boundaries of chiral antiferromagnetic slabs is important for the design of prospective antiferromagnetic spintronic devices. Here, we derive the transition from spin lattice to micromagnetic nonlinear $\sigma$-model with the corresponding boundary conditions for a chiral cubic G-type antiferromagnet and analyze the impact of the slab boundaries and antisymmetric exchange (Dzyaloshinskii--Moriya interaction) on the vector order parameter. We apply this model to evaluate modifications of antiferromagnetic domain walls and skyrmions upon interaction with boundaries for different strengths of the antisymmetric exchange. Due to the presence of the antisymmetric exchange, both types of antiferromagnetic solitons become broader when approaching the boundary and transform to a mixed Bloch--Néel structure. Both textures feel the boundary at the distance of about 5 magnetic lengths. In this respect, our model provides design rules for antiferromagnetic racetracks, which can support bulk-like properties of solitons.

12 pages, 5 figures, 71 reference

References in corpus (8)

• Electric-Field-Controlled Antiferromagnetic Spintronic Devices
• Surface twist instabilities and skyrmion states in chiral ferromagnets
• Spin eigen-excitations of an antiferromagnetic skyrmion
• Theory of Dzyaloshinskii domain wall tilt in ferromagnetic nanostrips
• Boundary-Driven Twist States in Systems with Broken Spatial Inversion Symmetry
• Asymmetric dynamics of edge exchange spin waves in honeycomb nanoribbons with zigzag and bearded edges boundaries
• Boundary conditions at the interface of finite thickness between ferromagnetic and antiferromagnetic materials
• Discretized dynamics of exchange spin wave bulk and edge modes in honeycomb nanoribbons with armchair edge boundaries